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Aluminum mig help needed!

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  • Aluminum mig help needed!

    Hi guys, trying to learn to weld some aluminum, have a millermatic 251 with 30a spool gun. Have watched a bunch of videos on this and am confused?
    i see most telling me to use spray transfer and have a hiss sound instead of crackle sound. I can get that sound but it seams real hard not to burn back tips?
    i seem to get a better weld with the other setting but got splatter. I'm not a welder so it is Greek to me. Is it just that I need more practice with it? A guy I know came by and herd the hiss and told me I don't want that. He is a certified welder
    if so why do the videos say it??
    thanks

  • #2
    Welding by the sound is a rather subjective measure, but once you get a machine dialed in for a good weld on aluminum, the sound is a good indicator to let you know how the weld is doing. In other words, get a good, clean weld with good penetration and get used to the sound that is produced, then the sound will help guide you in changing settings for different material thickness, etc. Having said that, I get more of a crackle than a hiss when I weld aluminum, but the crackle is a very even crackle. If the crackle is intermittent or has a lot of "pops" then I'm usually seeing more spatter. I do know people who weld aluminum with a standard mig process that get more of a hiss, but they have their voltage and wire feed turned up real high and their resulting travel speed is crazy fast.

    Focus first on surface prep. Aluminum needs to be clean and free of oxidation before you weld. Also make sure you have good gas flow at the nozzle and you are set for about 30 cfm (assuming you aren't using flux-core). If you are burning tips, decrease your voltage a little or increase your distance between the tip and the work a little. For aluminum, you want to push, not drag the weld, i.e., the tip is angled so it points slightly in the direction of travel.

    When I was first learning to weld aluminum, I would keep notes listing material thickness, joint type, welding position, wire size, voltage, feed rate, work angle, travel angle, travel speed, stick-out, etc., and descriptions of how the weld looked. I would try to change only one thing at a time so that I cold see the effect of each variable. I went through a lot of scrap pieces learning, but now I can usually set up a new or unfamiliar machine pretty fast, or determine the problem when something goes wrong.

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    • #3
      Have you ever made bacon? Heard that mmmmmm sizzling sound. Same as the sound you'll hear welding AL.

      What wire do you have?, and I'd assume that your using straight Argon.

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      • #4
        when I want to lay down a flat weld with a nice look to it I will set the machine a bit hotter and have the hiss sound but for just plain old welding I normally have the crackling sound sort of like the bacon frying sound like cruiser mentioned.

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        • #5
          It is a different sound than short circuit mig, a lot smoother. Lots of certified welders have never laid eyes on a spoolgun. Once you have it set up right you pull the trigger and haul ass! It goes a lot faster than sc on steel as well, and if you pause, or go too slow them you burn through.

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          • #6
            Aluminum mig help needed!

            I haven't welded aluminum mig for that long (we do pulse at work) but when I do weld it I like to have just a little more crackle then a hiss. Like others have mentioned you can get the crackle by turning up wire speed. I would guess that you're burning tips because you're wire speed is a good bit too low. And remember aluminum has a lot smaller range of operation to get a good weld than steel does. But hang in there and listen to all these other guys and you'll get it in no time!

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            • #7
              Here is a pretty good video on the subject...

              think this may illustrate better than words...

              http://www.youtube.com/watch?v=8AT4cEHtMn8

              Sights & Sounds...Courtesy of Jody... weldingtipsandtricks
              Last edited by H80N; 10-01-2013, 06:23 PM.

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              • #8
                Also, you need to be pushing the gun, not pulling.

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                • #9
                  Aluminum

                  Thanks guys, been trying a bunch more scraps, getting better. I had looked at that video before and the spray sound he was after is what I have so much trouble with. I can get that sound but burn tips like crazy
                  mostly on start up, can't quite get the relationship between wire feed and volts
                  If you leave the volts alone but change wire speed it does seem to change the way it acts? Would be nice to have a video showing the why and how of the process

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                  • #10
                    spray arc does not happen unless the shielding gas has oxygen in it and you can't use a shielding gas with oxygen in it when welding aluminun

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                    • #11
                      Originally posted by 6g 7018 View Post
                      spray arc does not happen unless the shielding gas has oxygen in it and you can't use a shielding gas with oxygen in it when welding aluminun
                      Fishbum disregard this as it is pure BS. Also make sure your wire is not touching the work piece when you pull the trigger. With short circuit you can get away with it but when setup for spray you can get burn backs.

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                      • #12
                        practice, practice, practice!

                        I used to run with the same set up @ my previous place of employment. One thing I would mention is check your wire tension in the spool gun. I had similar issues after setting up my machine to weld t6061 1/8 aluminum. I scratched my head till I started to relieve the tension on my wire. Er4043 especially because it's really ductile. Try some er5356 spools. Er5356 is a Lil more rigid and feeds better. Down set is, you will have to change your settings and prepare for more fumes.

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                        • #13
                          Here is one that illustrates 30A setup...

                          http://www.youtube.com/watch?v=Fl1h_c7z-R8

                          ADDITIONALLY....

                          All of the sources that I have found recommend a 3/4 inch stickout for Aluminum with a spoolgun to avoid burnback...

                          Here is the generic Miller spoolgun hookup and settings video..

                          http://www.youtube.com/watch?v=gn6zyjboa4c
                          Last edited by H80N; 10-03-2013, 08:06 AM.

                          Comment


                          • #14
                            Fishburn, Everyone here has given you great advise except for 6G.

                            The only thing extra that I would like to add that no one mentioned is that I like to set my voltage which is the heat and once that is where I want it I will then start welding and adjust the wire speed knob while I'm welding to fine tune it in.

                            You need to find the point where your not getting the burn back.

                            Good luck.

                            Comment


                            • #15
                              Originally posted by Portable Welder View Post
                              Fishburn, Everyone here has given you great advise except for 6G.

                              The only thing extra that I would like to add that no one mentioned is that I like to set my voltage which is the heat and once that is where I want it I will then start welding and adjust the wire speed knob while I'm welding to fine tune it in.

                              You need to find the point where your not getting the burn back.

                              Good luck.


                              Portable Welder, that's a great piece of advise, its how I dial in a perfect setting too. Short curcuit welding= wire speed too fast, Burn back to tip= wire speed too slow. That's how I understand it.

                              JA

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